Norville Wendy
Institute of Marine Affairs, P.O. Box 3160, Carenage P.O., Trinidad and Tobago, W.I.
Rev Biol Trop. 2005 May;53 Suppl 1:33-40.
The Gulf of Paria receives heavy metal input from urban runoff, industrial and agricultural activity, sewage and domestic wastes: both from the west coast and from inland areas of Trinidad. Non-residual concentrations of nine metals, as well as total mercury concentrations, were used to determine spatial distributions of heavy metals in sediments in the Gulf of Paria. Surficial sediment samples were collected at 37 stations, which included the mouths of 11 major rivers that flow into the Gulf of Paria. Stations were sampled twice during the wet season (July 1998 and November/ December 1998) and twice during the dry season (March 1999 and April 1999). Sediments were analyzed for aluminium (Al), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), zinc (Zn) and mercury (Hg). Total Organic Carbon (TOC) and grain size analyses were also performed on the sediments. Principal component analysis showed that sediments from river mouths subject to greatest land use and anthropogenic input, were distinct from other sediments in the Gulf of Paria. This was due to higher Pb, Zn, Cu and Hg concentrations (3.53-73.30 microg g(-1), 45.8-313.9 microg g(-1), 8.43-39.71 microg g(-1) and 0.03-0.10 microg g(-1), respectively). Sediments further from the coast were also distinct due to their higher Al, Fe, Cr and Mn concentrations (1.37-3.16 mg g(-1), 9.51-18.91 mg g(-1) , 17.22-28.41 microg g(-1) and 323.6-1,564.2 microg g(-1), respectively). Cd and Pb were higher in the wet season while Ni was higher in the dry season. Pb, Zn, Cu and Hg were correlated with each other and with TOC. Correlation was also observed between Al, Fe, Cr, Mn and Ni. Al, Fe, Cr and Mn were correlated with percentage clay in sediments. The results suggest that Pb, Zn, Cu and Hg are preferentially removed by organic matter, which settles at the river-mouths, while Al, Fe, Cr, Mn, and Ni become associated with clay minerals and are transported away from the coast.
帕里亚湾接收来自城市径流、工农业活动、污水及生活垃圾的重金属输入，这些来源既有来自特立尼达西海岸的，也有来自内陆地区的。利用9种金属的非残留浓度以及总汞浓度来确定帕里亚湾沉积物中重金属的空间分布。在37个站点采集了表层沉积物样本，其中包括流入帕里亚湾的11条主要河流的河口。在雨季（1998年7月和1998年11月/12月）对站点进行了两次采样，在旱季（1999年3月和1999年4月）也进行了两次采样。对沉积物分析了铝（Al）、镉（Cd）、铬（Cr）、铜（Cu）、铁（Fe）、铅（Pb）、锰（Mn）、镍（Ni）、锌（Zn）和汞（Hg）。还对沉积物进行了总有机碳（TOC）和粒度分析。主成分分析表明，来自土地利用和人为输入最多的河口的沉积物，与帕里亚湾的其他沉积物不同。这是由于较高的铅、锌、铜和汞浓度（分别为3.53 - 73.30微克/克、45.8 - 313.9微克/克、8.43 - 39.71微克/克和0.03 - 0.10微克/克）。离海岸较远的沉积物也有所不同，因为它们的铝、铁、铬和锰浓度较高（分别为1.37 - 3.16毫克/克、9.51 - 18.91毫克/克、17.22 - 28.41微克/克和323.6 - 1564.2微克/克）。镉和铅在雨季含量较高，而镍在旱季含量较高。铅、锌、铜和汞彼此之间以及与TOC都存在相关性。在铝、铁、铬、锰和镍之间也观察到了相关性。铝、铁、铬和锰与沉积物中的黏土百分比相关。结果表明，铅、锌、铜和汞优先被有机物去除，这些有机物沉淀在河口，而铝、铁、铬、锰和镍与黏土矿物结合，并被带离海岸。
